(2) Preservation from external cold is highly important. When a nerve of the arm, or leg, or trunk, is affected, warm flannel under-clothing ought immediately to be adopted. The patient who has been suffering from cervico-occipital neuralgia should for some time, in anything but quite summer weather, never go out without wearing a warm comforter round the neck. The sufferer from facial neuralgia should for some time after the cessation of actual attacks never face wind without wearing a thick veil.
(3) Exposure to bright light must be scrupulously avoided by sufferers from ophthalmic neuralgia. The affection known as "snow-blindness" is really a neuralgia, with vaso-motor complications, produced by the glare of light reflected from snow; and one of the severest attacks of neuralgia which I personally ever experienced was provoked in this way. Even the comparatively slighter, but for an Englishman unusual, glare of sunlight which one meets with during the first days of a Continental holiday, in wandering about towns made up of clean white stone or whitewashed houses, is enough to provoke an attack, unless the eyes are carefully guarded with colored glasses.
(4) It is scarcely necessary, after what has been already said, to insist upon the absolute necessity of mental quietude, as far as this can be obtained. This precaution is more or less important in all neuralgic affections; but in migraine and in other trigeminal neuralgias it is almost of more consequence than any other prophylactic measure; and in angina pectoris it is so essential that adoption or neglect of it may easily turn the scale between life and death. All forms of abdominal visceral neuralgia, also, are greatly affected by emotion, and passion or strong excitement of any kind must be scrupulously shunned if the neuralgic habit is to be broken through. Unfortunately, it too often happens that the mental surroundings of the patient cannot be so changed as to enable us to carry out this kind of prophylaxis effectually; and neuralgic cases of this class are among the severest trials of the physician's tact and skill, and too frequently defy his efforts.